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Hifiman Sundara Review (headphone)

amirm

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This is a review and detailed measurements of the Hifiman Sundara planar magnetic open back headphone. It was kindly sent to me by one of their retailers, Apos Audio and costs US $349.

The Sundara looks elegant and no less so than higher up in the line from Hifiman:

hifiman sundara review.jpg


The cups don't swivel. That, and being new made for slightly uncomfortable feeling around my ears. The weight is inline with other headphones in this class at 390 grams. The cup is round and has inside diameter of 59 mm and depth of 18 mm.

The included cord is short and comes with right angle connector. It has a nice (silicon?) insulator. It did not seem microphonic to me.

Note: The measurements you are about to see are preformed using standardized GRAS 45CA headphone measurement fixture. Headphone measurements require more interpretation than speaker tests and have more of a requirement for subjective testing as a result. In addition, comparison of measurements between different people performing it using different configurations requires fair bit of skill. So don't look for matching results. Focus on high level picture. Listening tests are performed using RME ADI-2 DAC and its headphone output.

Mounting the headphone on the test fixture was super easy requiring no manipulation to get left and right to match at dual frequencies.

Hifiman Sundara Measurements
As usual, we start with our stereo frequency response measurements:
hifiman sundara frequency response measurements.png


I like the near compliance with preference curve form upper bass to lower treble. The former though as you can see, droops as many headphones do. The peaks above 5 kHz also exceed our target which you can better see in a relative graph:

hifiman sundara relative frequency response measurements.png


There is a bit of shortfall around 2 kHz as well which I tend to like! No, it is not good that way but it means that once I compensate for it, it should open the sound more.

Distortion shows little unexpected other than something going on between 6 and 7 kHz:

hifiman sundara distortion measurements.png


hifiman sundara THD distortion measurements.png


This is much better than Hifiman Ananda:

index.php


Group delay shows the typical messiness we see in mid-frequencies which seems to have a role in (good) spatial effects:

hifiman sundara Grou Delay measurements.png


Impedance is flat at 40 ohm meaning you need current more than voltage to drive the Sundara:
hifiman sundara Imnpedance measurements.png


Efficiency is slightly below average:

most efficient planar magnetic headphone.png


Hifiman Sundara Listening Tests
I had been listening to my AKG K371 for a few hours before swapping it with Sundara. The difference was startling in how open and expansive the sound became with Sundara. Alas, I quickly realized there is no sub-bass being produced. And sound signature was a bit bright and over exaggerated at the top. So out came the EQ tool:

hifiman sundara equalization eq.png


Oh wow! The transformation was dramatic. Sub-bass came into play like nobody's business. Even at lower volumes I could feel the nice vibrations in my head! :) The notch filter took care of the highs being exaggerated and a bit harsh. And the fine but broad filter around 2.1 kHz helped the spatial qualities improve even more. Overall tonality now was warm with tons of detail especially in string instruments. Very lovely.

As a verification, I asked my son to come over and without looking at the measurements and EQ, listen to the headphone plain and then with EQ I had built above. After about half hour of listening he said there was no sub-bass and the there was something missing in the sound. With EQ he found the sound to be much improved causing him to say he likes it. So good correlation with my findings.

Conclusions
We have had a checkered history with Hifiman so far with HE-6 performing very well and the Ananda, not so much. It is nice to discover that Sundara, despite its much lower price than either two, brings a competent implementation to the table. Objectively we miss the bass by a mile but otherwise, compliance to our target is very good. Distortion while not best in class, is kept much more under control than Ananda. Likely the smaller driver is able to be much more optimized here.

Without EQ, I would not be a buyer as I love my deep bass response and highs that are a bit more sedated. With EQ, the Sundara transforms beautifully providing excellent spatial effect with respect to instrument and channel separation while providing the deep bass response that I crave.

I am happy to give a strong recommendation to Hifiman Sundara with equalization.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

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  • Hifiman Sundara frequency response.zip
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sweetchaos

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To import this PEQ profile into 'Equalizer APO', use:
Preamp: -8.6 dB
Filter 1: ON LS Fc 50 Hz Gain 8.0 dB Q 1.0
Filter 2: ON PK Fc 2112 Hz Gain 2.5 dB Q 1.5
Filter 3: ON PK Fc 6300 Hz Gain -4.0 dB Q 4.0
Otherwise, see my PEQ guide.
..................................................................................................................
For those who don't have PEQ-capable app, and want to use GEQs instead.
Preamp: -7.7db
32 7.2
64 1.0
125 -0.4
250 -0.2
500 -0.1
1000 -0.4
2000 2.5
4000 -0.5
8000 -2.0
16000 -0.1
Preamp: -7.0db
20 4.7
25 5.1
32 4.7
40 3.9
50 2.7
63 1.6
80 0.6
100 0.2
125 -0.0
160 -0.1
200 -0.1
250 -0.1
315 -0.1
400 -0.2
500 -0.1
630 -0.1
800 -0.1
1000 0.0
1250 0.2
1600 0.8
2000 2.0
2500 1.5
3150 0.4
4000 0.1
5000 -0.3
6300 -4.3
8000 -0.5
10000 -0.3
12500 -0.3
16000 -0.4
20000 -0.2
If you want to import into "Wavelet" (Android App):
GraphicEQ: 20 -0.2; 21 -0.2; 22 -0.2; 23 -0.2; 24 -0.2; 26 -0.2; 27 -0.2; 29 -0.2; 30 -0.2; 32 -0.2; 34 -0.2; 36 -0.4; 38 -0.7; 40 -1.0; 43 -1.4; 45 -1.7; 48 -2.1; 50 -2.4; 53 -2.8; 56 -3.2; 59 -3.5; 63 -3.9; 66 -4.2; 70 -4.5; 74 -4.7; 78 -5.0; 83 -5.2; 87 -5.3; 92 -5.5; 97 -5.6; 103 -5.8; 109 -5.9; 115 -6.0; 121 -6.0; 128 -6.1; 136 -6.1; 143 -6.2; 151 -6.2; 160 -6.2; 169 -6.3; 178 -6.3; 188 -6.3; 199 -6.3; 210 -6.3; 222 -6.3; 235 -6.4; 248 -6.4; 262 -6.4; 277 -6.4; 292 -6.4; 309 -6.4; 326 -6.4; 345 -6.4; 364 -6.4; 385 -6.4; 406 -6.4; 429 -6.4; 453 -6.4; 479 -6.4; 506 -6.4; 534 -6.3; 565 -6.3; 596 -6.3; 630 -6.3; 665 -6.3; 703 -6.3; 743 -6.3; 784 -6.2; 829 -6.2; 875 -6.2; 924 -6.1; 977 -6.1; 1032 -6.0; 1090 -6.0; 1151 -5.9; 1216 -5.8; 1284 -5.7; 1357 -5.6; 1433 -5.4; 1514 -5.2; 1599 -5.0; 1689 -4.7; 1784 -4.5; 1885 -4.2; 1991 -4.0; 2103 -4.0; 2221 -4.0; 2347 -4.2; 2479 -4.5; 2618 -4.7; 2766 -5.0; 2921 -5.3; 3086 -5.5; 3260 -5.7; 3443 -5.8; 3637 -6.0; 3842 -6.1; 4058 -6.2; 4287 -6.4; 4528 -6.6; 4783 -6.8; 5052 -7.1; 5337 -7.6; 5637 -8.4; 5955 -9.5; 6290 -10.2; 6644 -9.7; 7018 -8.6; 7414 -7.8; 7831 -7.3; 8272 -7.0; 8738 -6.8; 9230 -6.7; 9749 -6.6; 10298 -6.6; 10878 -6.6; 11490 -6.5; 12137 -6.5; 12821 -6.5; 13543 -6.5; 14305 -6.5; 15110 -6.4; 15961 -6.4; 16860 -6.4; 17809 -6.4; 18812 -6.4; 19871 -6.3
Otherwise, see my GEQ guide.
 
Last edited:

dfuller

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I just don't understand Hifiman's product stack. Some of their stuff seems to be great, and some of it seems to be crap, and price has literally zero bearing on which is which.

Also - considering most planars seem to have a distortion spike somewhere in the presence region (and, if you look on a CSD waterfall plot, you'll see they ring pretty bad right around that same point), I wonder if maybe that's the resonance caused by the tensioning of the driver diaphragm and insufficient damping. Let me go find some measurements, I'll report back.

ETA: measurements from SBAF of the Monoprice Monolith M1060, another planar. Long presence region resonance tracks directly with a distortion spike at the same frequency as well as a frequency response spike.
1618542830365.png

1618542637885.png

1618542677520.png
 
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GDK

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Clearly, I was looking forward to this. And while I thought there was a risk that the review was not positive given how the Ananda performed, I was not worried because it didn’t matter to me. I think these are amazing headphones, although I do prefer the Oratory1990 PEQ to Amir’s (sorry :facepalm:).
 

Anmol

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May be it's my head's shape or some other effect, changing to dekoni pads changed how sundara sound with noticeable increase in bass and reduction in brightness.
Given how popular this headphone is, If there was a dekoni pad around suitable for he series, it would be interesting to see comparable data with hifiman pali pad vs dekoni on sundara
Many thanks
 

KiyPhi

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Good to see this review. I feel like it should be noted that the lower end performance on these depends on the seal and it will vary from head to head. I get a nice low rumble with these naturally. Others have measured the on head to extend down to 20Hz no issue. These have been my go to recommendation for years and are a great headphone and take to EQ like a champ. Only drawback is, as Amir noted, the lack of swivel but you can swap headbands to fix this if you really want to.
 

Music1969

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oratory1990's measurement looks generally similar, at a 'high level' view

1618547925036.png
 

frix

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Nice to see there are more reasonable priced great performing headphones. Though what is it with hifiman and cup swifel? Why hifiman? Why? Was the swifel a weak point in former designs? And instead of improving they just killed it?
 

luft262

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Thank you Amir! These are my daily drivers, along with the JDS Atom DAC and AMP. I love these headphones and I'm glad the science backs it up. I'm going to try your EQ settings out. I generally use the stock EQ in Wavelet for my cans, but I'm excited to play with the EQ a little! What audiophiles aren't using EQ these days anyway???

P.S. Thanks for the Ananda review too. I'll stick with my Sundaras or hold out for the Arya review!
 

paolomo

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Thanks for the detailed review! I like mine, a lot. Peak here, shelf there, and they shine, that was my first successful EQ attempt ever. My impression is that a pair of Sundara and a random pick from the HD 600/650/660s/6XX family can make a lot of people happy.

(ok, a random pick or two :D )
 
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